A critical analysis on green and low-temperature methods for the production of carbon nanoparticles

Carbon nanoparticles (CNPs) gained a growing attention for a wide multiplicity of applications. CNPs offer the basic advantage of being well tolerated by living organisms and they are much more environmental friendly than many other inorganic NPs for analogous purposes. In this short review, several techniques are described and compared, enlighting their strenghts and drawbacks in terms of easy of deployment, possibility of transfer on a large scale, plant safety and environmental soundness. The latter aspect is now one of the basic paradigms for the chemical production tout court and this target can be achieved by acting on different fronts, namely energy saving, cleaner processes and reagents substitution. Some techniques are still confined to a laboratory scale and they need deeper investigations before being transferred to an industrial production, while some other have reached a technological maturity to make them competitive on the market. The methods for the synthesis of CNPs have been grouped according to a scheme different from the usual classification in top-down and bottom-up processes. A greater emphasis has been given to the simplicity of unit operations and to the corresponding energy burden.